Methods for controlled production of security documents are already known in the art. U.S. Pat. No. 4,633,395 for instance discloses such a method wherein sheets of security documents are tracked throughout the production process. Before travelling through a first processing station, each sheet is provided with a unique sheet identification code on an edge thereof, which sheet identification code is stored in a computer. Before and after each operation in the successive processing stations, the sheet identification codes are read by automatic reading units. In this way, each individual sheet can be followed during its various operations and the possible loss of a sheet can be identified immediately. International application WO 02/083423 A1 discloses a similar solution wherein sheets can be tracked individually throughout the whole production process. According to this other solution, the sheet identification codes of a plurality of sheets are transferred to a central database over a data network in a single data packet.
While the above solutions are efficient in tracking individual sheets throughout the whole production process, such solutions are however insufficient when dealing with situations where complex production tasks have to be undertaken, especially when a plurality of distinct production jobs have to be executed in a same printing plant. The tracking of individual sheets is furthermore rather cumbersome to manage in practice as the amount of data to process is considerable.
US patent application No. U.S. 2004/0193465 A1 discloses an automated workflow assignment method designed to enable the submission over the internet (or like computer networks) of print jobs to commercial print shops for printing.
US patent application No. U.S. 2007/0041034 A1 discloses a wireless workflow system for a commercial print shop which is designed to facilitate the work of operators and managers in large-scale commercial print shops.
US patent application No. U.S. 2007/0113164 A1 discloses a system and method for managing the production printing workflow in commercial print shops.
While the solutions disclosed in the above U.S. patent applications might be suitable to deal with jobs and workflows in commercial printing environments, such solution are however not suited for dealing with the production of security documents as such production involves highly specific printing and processing steps performed on printing and processing equipment that is not available to commercial printers.
Nowadays, the production of security documents, especially of banknotes, has become a complex task and involves more processes, machinery and decision-making than ever before. Such complexity and diversity make it even more difficult to manage the production of security documents in an efficient way.
The production of banknotes in particular involves several successive printing and processing operations including:                offset printing for typically printing the colour backgrounds of the banknotes;        silk-screen printing for printing iridescent and/or optically-variable ink patterns;        foil stamping for applying optically-variable devices (OVD's) such as metallic patches, holograms or the like;        intaglio printing for printing one or both sides of the banknotes with complex patterns exhibiting a characteristic tactility and appearance (e.g. portraits or other pictorial representations, latent images, guilloche patterns, alphanumerical information, etc.);        letterpress printing for printing variable information such as signatures, dates and serial numbers (which serial numbers are unique to each individual banknote);        the application of protective coatings, in particular by varnishing, to increase the durability and life cycle of the banknotes;        finishing, which finishing typically involves the processing and cutting of the printed sheets or web into individual banknotes and packing of the individual banknotes into banknote bundles and packs of banknote bundles;        quality control to ensure that the banknotes being produced meet the desired quality requirements.        
Additional operations that can be carried out on the banknotes during their production may further include the provision of markings by ink-jet printing, laser marking, micro-perforation, etc.
Considering the high diversity of processes and machinery involved in the production of banknotes, or like security documents, there is a considerable risk that human errors occur during the production and that whole production batches are wrongly processed or even damaged, which in turn affects the production efficiency and costs.
Furthermore, as production schedules become tighter and efforts are made to reduce work-in-progress, production managers are faced with the challenge of planning and managing the production process at higher levels of efficiency, ensuring that deadlines and budgets are respected.
Moreover, there is an increasing trend for the research and development of high security features to fight counterfeiting, which security feature combine and necessitate different printing and processing steps in order to be produced. Such high security features imperatively require a very tight control of the production of the security documents.
There is therefore a need for a method and system enabling machine operators, supervisors and managers working in the printing plant to take critical informed decisions based on precise and up-to-date data, locally or centrally.